1. Field of the Invention
The present invention relates to a process for permanent hair-styling, characterized in that first only the hair near the scalp is fixed and then the middle parts and tips of the hair shaped and then in a second step fixed, and to means for performing the process.
2. Prior Art
Permanently waving originally straight hair (called a permanent wave or perm) is known to be intended primarily to lend greater fullness and volume to a head of hair and to make the style longer-lasting.
The classic technique of performing the permanent hair-styling comprises, in a first step, opening up the disulfide bonds of the hair keratin with the aid of an agent that contains a reducing ingredient (hair-styling means); then the hair is shaped as desired; and then the disulfide bonds are linked up again, using an agent (fixing agent) that contains an oxidizing ingredient. As reducing ingredients, sulfites, thioglycolic acid, thiolactic acid, 3-mercaptoproprionic acid, mercaptocarboxylic acid and cysteine are used in particular. As the fixing agent, liquids that contain hydrogen peroxide and bromate are used in particular.
The wet hair is typically wound onto suitable shaping bodies (typically, curlers); the waving solution is then applied and after an appropriate action time is rinsed out again. The fixing agent is then applied in the form of liquid or foam to the hair, which is on curlers, and after an adequate action time is then rinsed out again; after that the hair is taken down from the curlers and re-fixed.
However, this process has a number of disadvantages. One of these disadvantages is due to the variable structure of the hair from the scalp to the tips. The middle parts and the tips, in particular, behave differently in the course of styling, as a function of aging or the effects of light and moisture as well as such previous chemical treatments as perming and coloring. As a consequence, the tips of the hair, which are especially stressed anyway, end up tightly curled, while the undamaged hair near the scalp is softly waved. This kind of overall wave pattern looks unnatural, and the resultant tangling and splitting of the tips can lead to further damage to the hair.
Moreover, as fashions in hair-styling, and the taste of the time, change, there is no longer a demand for relatively pronounced reshaping of the hair. To use the terms generally employed by customers in this respect, there is excessive and undesirable frizziness.
To attain the object of a permanent wave as stated above, however, a well-defined curl at the scalp is absolutely indispensable. If one seeks to meet this precondition with suitable provisions such as thin curlers, strong waving preparations, longer action times, etc., then as a rule the hair middle parts and the tips of the hair are necessarily waved too strongly--that is, are too frizzy--and moreover the hair structure suffers undue stress. Conversely, to achieve a desired soft or natural waving of the shank and end of the hair, the requisite tight curl at the scalp is inadequate, i.e. too weak. The teaching of published, unexamined German patent application DE-OS 3 119 634 filed by the Applicant of the present patent application seeks to solve this problem in a two-step reduction treatment by treating the entire head of hair with a weak styling means and then treating the hair near the scalp with a thickened, stronger styling means. This is intended to spare the hair and to produce a more uniform wave pattern. The disadvantage of this procedure, though, is first a more-complicated technique, and second that nevertheless there is an increased tightness of the curl at the middle parts and ends.